Integrated circuit test systems for component testing in a burn-in chamber are well known; for example semiconductor life tests in burn-in chambers are common. The process of burning-in typically consists of applying a load to the components being tested at elevated temperatures. This allows identification of weak or faulty components and thus precludes their ultimate use such as in a computer system. The burn-in chambers generally comprise a plurality of paired opposed tracks which carry the burn-in trays, connectors and a power supply.
Integrated circuit boards including connectors, sockets, etc. are secured to the burn-in trays. The sockets may be longitudinally bussed to a ribbon plug as is well known. There may be positioned within the socket any number of elements to be tested for example semiconductor devices.
The burn-in trays which carry the boards are generally rectangular in shape with open bottoms and simply slide on the paired tracks in the burn-in chamber.
The prior art burn-in trays are subject to various problems. With the open bottom care must be taken in placing the trays on a surface to prevent an object from striking the board or the components secured to the board. More importantly, the burn-in trays require special cabinets for storage which adds to the total cost of the burn-in process.
Additionally when the trays are being inserted into a burn-in chamber if they are not carefully handled they will tilt causing the components secured to the board to strike an above tray, or the tilted tray will strike the components of a lower tray resulting in damage. Further when a tray is disengaged from a connector, which is typically located on the rear wall of the burn-in chamber, there is a tendency to lift the burn-in tray prior to disengaging and this results in damage both to the plug mating with the connector and the connector.
My invention overcomes all these prior art difficulties and provides a stackable floored tray which eliminates the need for a separate storage cabinet. Further the tray is structured to prevent tilting when inserted into or when removed from a burn-in chamber.
My invention broadly comprises a burn-in tray adapted for nesting with like trays and structured to insure movement only in a plane substantially parallel to the plane in which lie the parallel opposed tracks in the burn-in chamber.
In one embodiment my invention comprises a burn-in tray with a floor having a one end and another end and opposed sides, upwardly extending walls joined to the ends by bends, the bend characterized by at least one opening therein. The upper edges of the walls include tab members, each tab member having a cammed surface which surface is adapted to engage the opening in the bend of a next succeeding tray. Thus the tab is received in the opening of the bend of the next succeeding tray and telescopically engaged therewith.
The sides of the tray include at least one finger extending outwardly from the floor. The finger defines with the edge of the board secured to the tray a guide member which engages the track of the burn-in chamber to prevent tilting of the tray.
In the preferred embodiment the burn-in tray is a planar substantially elongated tray comprising a floor having walls at either end connected to the floor by bends. The bends are characterized by at least one slot therein. The upper edge of each wall teminates with at least one tab having a camming surface which surface slopes upwardly and inwardly toward the opposed wall. The tabs are adapted to be received in the slots of a bend of a next succeeding burn-in tray. The cam surface guides the tab into the slot until seated. When seated the trays are then secured one to the other and movement along any axis is prevented.
Formed on the sides of the floor are fingers extending outwardly and downwardly with reference to the plane of the floor. When the board is secured to the tray the edge of the board defines with the fingers a guide member. When the tray is inserted in the burn-in chamber the tracks in the chamber are straddled by the guide members.